U.S. Pat. No. 4,941,018, Kasamura issued Jul. 10, 1990 shows a rack and pinion mechanism (FIG. 27) in an electrophotographic copier with interchangeable development stations. The development stations are movable (FIG. 27) through a position aligned with a development position. The stations are moved through a vertically oriented guide shaft attached to the external portion of the apparatus.
U.S. Pat. No. 4,947,215 granted to Chuang, Aug. 7, 1990 shows a liquid development mechanism in which four development stations are positioned on a "trolley" which translates. No details of the mounting of the trolley are given.
In recent years, small desk top printers have been designed for easy manufacturing with a limited number of metal fastening devices, for example, a minimum number of bolts or screws. These printers include as much as possible the use of plastic snap fitting parts which, for example, are molded to a pair of multifunctional mechanism plates.